Laser cooling may be used for cryogenic cooling applications (e.g., cooling of components such as detectors, satellite components, etc.) and for cooling of laser crystals. In the latter case, the cooling can be used to augment or supplant the usual conduction cooling of the laser crystal in a bulk or gross fashion.
Laser cooling occurs when laser light is absorbed by a medium, causing the medium to subsequently re-radiate light at a higher frequency (energy). In some cases, a small majority of the photons spontaneously emitted by the medium are higher in energy than the absorbed laser photons, resulting in a net heat loss of the medium. Thus, the efficiency of laser cooling the medium may be limited by an amount of photons that the medium absorbs and a probability of the medium emitting light at a higher frequency than the absorbed laser light.